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| author | Jesse Brandeburg <jesse.brandeburg@intel.com> | 2020-06-05 01:50:27 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-05 04:06:25 +0200 |
| commit | c348c16305280fe3e6c1186378f96c8634c149f9 (patch) | |
| tree | aa53fa861170b36756d7d1aa14c1ce4c00089da5 /lib/Kconfig.debug | |
| parent | lib/flex_proportions.c: cleanup __fprop_inc_percpu_max (diff) | |
| download | linux-c348c16305280fe3e6c1186378f96c8634c149f9.tar.xz linux-c348c16305280fe3e6c1186378f96c8634c149f9.zip | |
lib: make a test module with set/clear bit
Test some bit clears/sets to make sure assembly doesn't change, and that
the set_bit and clear_bit functions work and don't cause sparse warnings.
Instruct Kbuild to build this file with extra warning level -Wextra, to
catch new issues, and also doesn't hurt to build with C=1.
This was used to test changes to arch/x86/include/asm/bitops.h.
In particular, sparse (C=1) was very concerned when the last bit before a
natural boundary, like 7, or 31, was being tested, as this causes sign
extension (0xffffff7f) for instance when clearing bit 7.
Recommended usage:
make defconfig
scripts/config -m CONFIG_TEST_BITOPS
make modules_prepare
make C=1 W=1 lib/test_bitops.ko
objdump -S -d lib/test_bitops.ko
insmod lib/test_bitops.ko
rmmod lib/test_bitops.ko
<check dmesg>, there should be no compiler/sparse warnings and no
error messages in log.
Link: http://lkml.kernel.org/r/20200310221747.2848474-2-jesse.brandeburg@intel.com
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
CcL Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/Kconfig.debug')
| -rw-r--r-- | lib/Kconfig.debug | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 30302c9b0f83..b9a450b1fbf7 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2022,6 +2022,19 @@ config TEST_LKM If unsure, say N. +config TEST_BITOPS + tristate "Test module for compilation of clear_bit/set_bit operations" + depends on m + help + This builds the "test_bitops" module that is much like the + TEST_LKM module except that it does a basic exercise of the + clear_bit and set_bit macros to make sure there are no compiler + warnings from C=1 sparse checker or -Wextra compilations. It has + no dependencies and doesn't run or load unless explicitly requested + by name. for example: modprobe test_bitops. + + If unsure, say N. + config TEST_VMALLOC tristate "Test module for stress/performance analysis of vmalloc allocator" default n |